Semiconductor sensor and manufacturing method therefor

ABSTRACT

A semiconductor sensor is disclosed that includes a semiconductor substrate, a sensing portion provided on the semiconductor substrate, and a pad in electrical communication with the sensing portion and provided on the semiconductor substrate. The semiconductor sensor also includes a bonding wire in electrical communication with the pad. Furthermore, the semiconductor sensor includes a cover member with a covering portion disposed over the semiconductor substrate for covering the sensing portion such that the covering portion is separated at a distance from the sensing portion. The cover member further includes a coupling portion provided on the semiconductor substrate at an area including the pad and for enabling electrical connection of the pad with the bonding wire therethrough.

CROSS REFERENCE TO RELATED APPLICATION(S)

The following is based upon and claims priority to Japanese PatentApplication 2005-197412, filed Jul. 6, 2005, and is incorporated hereinin its entirety by reference.

FIELD OF THE INVENTION

The present invention generally relates to a semiconductor sensor and,more particularly, to a semiconductor sensor with a cover member and amethod of manufacturing the same.

BACKGROUND

Semiconductor sensors have been designed that include a semiconductorsubstrate, sensing portions provided over one surface of thesemiconductor substrate, and pads provided on the periphery of thesensing portions over the one surface of the semiconductor substrate. Insuch a semiconductor sensor, bonding wires are electrically connected tothe pads. Also, signals from the sensing portions are transmittedthrough the pads and through the bonding wires. (See e.g., JapanesePatent Application 2003-531017, which relates to U.S. Pat. No.6,951,824, and Japanese Patent Publication 2002-504026, which relates toU.S. Pat. No. 6,656,368.)

In these prior art semiconductor sensors, a cover member formed ofsemiconducting material can be provided over one surface of thesubstrate to protect the sensing portions. This cover member is formedthrough sacrificial layer etching and multiple film formation processesor by attaching it to a semiconductor substrate with low-melting glassor another suitable adhesive material.

The cover member covers the sensing portions, and yet the cover memberis separated from the sensing portions at a distance. Thus, the covermember is unlikely to contact the sensing portions. Also, foreign matteris unlikely to contact the sensing portions. Therefore, the sensingportions are appropriately protected, and sensor characteristics can bemaintained.

To maintain electrical connection between the pads and the bondingwires, the cover member covers the sensing portions over one surface ofthe semiconductor substrate, and the cover is spaced from the pads.

However, these prior art semiconductor sensors have certaindisadvantages. First, forming the cover member via sacrificial layeretching and multiple film formation processes can be difficult. Also, anattachment region between the sensing portions and the pads for couplingthe cover member is typically provided for coupling the cover member.This attachment is relatively large (e.g., 5 mm) and can undesirablyincrease the size of the semiconductor sensor. For instance, when thecover member is attached with adhesive material, the attachment regionis typically large to allow for possible flow of the adhesive material.

SUMMARY OF THE INVENTION

A semiconductor sensor is disclosed that includes a semiconductorsubstrate, a sensing portion provided on the semiconductor substrate,and a pad in electrical communication with the sensing portion andprovided on the semiconductor substrate. The semiconductor sensor alsoincludes a bonding wire in electrical communication with the pad.Furthermore, the semiconductor sensor includes a cover member with acovering portion disposed over the semiconductor substrate for coveringthe sensing portion such that the covering portion is separated at adistance from the sensing portion. The cover member further includes acoupling portion provided on the semiconductor substrate at an areaincluding the pad and for enabling electrical connection of the pad withthe bonding wire therethrough.

A method of manufacturing a semiconductor sensor is also disclosed thatincludes providing a sensing portion on a semiconductor substrate andproviding a pad in electrical communication with the sensing portion onthe semiconductor substrate. The method also includes providing a covermember with a covering portion and a coupling portion. The methodfurther includes providing the coupling portion of the cover member onthe semiconductor substrate on an area including the pads such that thecovering portion covers the sensing portion and such that the coveringportion is separated at a distance from the sensing portion. Moreover,the method includes electrically coupling a bonding wire to the padthrough the coupling portion for transmission of signals output by thesensing portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of one embodiment of a semiconductorsensor;

FIG. 2 is a schematic sectional view of the semiconductor sensor takenalong line II-II of FIG. 1;

FIG. 3 is a schematic sectional view of the semiconductor sensor takenalong line III-III of FIG. 1;

FIG. 4 is an enlarged view of the portion IV of FIG. 3;

FIG. 5 is a schematic sectional view illustrating another embodiment ofthe semiconductor sensor;

FIG. 6 is a schematic sectional view illustrating another embodiment ofthe semiconductor sensor;

FIG. 7 is a schematic plan view of the semiconductor sensor of FIG. 6;

FIGS. 8A and 8B are schematic sectional views illustrating anotherembodiment of the semiconductor sensor; and

FIGS. 9A and 9B are schematic sectional views illustrating otherembodiments of the semiconductor sensor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereafter, description will be given to embodiments of the invention. Inthe following drawings, identical or equivalent parts will be markedwith the same reference numerals for the simplification of description.

Referring initially to FIGS. 1-3, one embodiment of a semiconductorsensor S1 is illustrated. In one embodiment, the semiconductor sensor S1is a differential capacitive semiconductor acceleration sensor, one ofcapacitive mechanical quantity sensors. The semiconductor sensor S1could be as an acceleration sensor for automobiles or a gyro sensor forcontrolling the operation of air bags, ABS, VSC, and the like. However,it will be appreciated that the semiconductor sensor S1 could be of anytype and could be used in any manner without departing from the scope ofthe present disclosure.

As illustrated in FIG. 1 to FIG. 3, the semiconductor accelerationsensor S1 includes a semiconductor substrate 10. In one embodiment, thesemiconductor substrate 10 is formed by subjecting this semiconductorsubstrate 10 to a publicly known micromachining process. For instance,as illustrated in FIG. 2 and FIG. 3, the semiconductor substrate 10 is arectangular SOI (Silicon On Insulator) substrate 10. It has an oxidefilm 13 as insulating layer between a first silicon substrate 11 asfirst semiconductor layer and a second silicon substrate 12 as secondsemiconductor layer.

Trenches 14 penetrate the second silicon substrate 12 in the directionof the thickness of the second silicon substrate 12 in a predeterminedpattern. In the embodiment shown, for instance, there are formedcomb-like beam structures 20, 30, 40, which include a movable portion 20and fixed portions 30, 40.

The oxide film 13 is removed in regions where the beam structures 20 to40 are disposed (i.e., the portion indicated by the broken rectangularline rectangle 15 in FIG. 1). Thus, an opening 15 is formed in the oxidefilm 13 in the space enclosed by the broken rectangular line.

The movable portion 20 includes a long and thin rectangular spindleportion 21 and spring portions 22 coupled at both ends. The movableportion 20 is integrally coupled with anchor portions 23 a, 23 b throughthe spring portions 22 and is supported by them.

As illustrated in FIG. 3, the anchor portions 23 a, 23 b are fixed atthe rim of the opening 15, and the anchor portions 23 a, 23 b aresupported above the first silicon substrate 11. The spindle portion 21and the spring portions 22 are disposed over the opening 15.

As illustrated in FIG. 1, the spring portions 22 are in the shape ofrectangular frame in which two parallel beams are coupled with eachother at both ends. They have a spring function and are displaced in thedirection orthogonal to the direction of the length of the two beams.Through these spring portions 22, the movable portion 20 can bedisplaced above the first silicon substrate 11 in the direction of arrowX in response to an acceleration.

As illustrated in FIG. 1, the movable portion 20 has comb-like movableelectrodes 24. In this example, four movable electrodes 24 areprotrudingly formed on the left side and the right side of the spindleportion 21, respectively, and they face onto the opening 15. The movableelectrodes 24 can be displaced in the direction of arrow X as themovable portion 20 formed integrally with the spring portions 22 and thespindle portion 21.

The fixed portion 30 positioned on the left side of the spindle portion21 in FIG. 1 includes a plurality of left-side fixed electrodes 31 and awiring portion 32 for the left-side fixed electrodes 31. The fixedportion 40 positioned on the right side of the spindle portion 21 inFIG. 1 includes a plurality of right-side fixed electrodes 41 and awiring portion 42 for the right-side fixed electrodes 41.

The wiring portions 32, 42 are fixed over the oxide film 13. The wiringportions 32, 42 are fixed, respectively, at opposite sides of thesemiconductor sensor S1 adjacent the rim of the rectangular opening 15.The wiring portions 32, 42 are supported above the first siliconsubstrate 11 with the oxide film 13 interposed therebetween.

In embodiment shown in FIG. 1, the multiple fixed electrodes 31 aredisposed between the movable electrodes 24 on one side of the movableportion 20, and the fixed electrodes 31 are disposed between the movableelectrodes 24 on an opposite side of the movable portion 20. The fixedelectrodes 31, 41 are cantilevered over the opening 15 and are supportedby the respective wiring portions 32, 42.

Thus, a detection gap for detecting capacitance is formed in each gapbetween a side face of a movable electrode 24 and a side face of a fixedelectrode 31 or 41. In other words, the movable portion 20 and the fixedelectrodes 31, 41 opposed to the movable electrodes 24 of the movableportion 20 with detection gaps in-between are constructed as sensingportions 20, 31, and 41 that generate detection signals foracceleration.

Furthermore, a pad 30 a for the left-side fixed electrodes and a pad 40a for the right-side fixed electrodes are disposed in predeterminedpositions over the wiring portion 32 for the left-side fixed electrodesand the wiring portion 42 for the right-side fixed electrodes,respectively. A wiring portion 25 for the movable electrodes is formedso that it is integrally coupled with one anchor portion 23 b. A pad 25a for the movable electrodes is formed in a predetermined position overthis wiring portion 25. The pads 25 a, 30 a, and 40 a for the respectiveelectrodes are formed by sputtering or evaporating aluminum, forexample.

Thus, the semiconductor acceleration sensor S1 includes the sensingportions 20, 31, and 41 provided over the surface of the semiconductorsubstrate 10 (i.e., over the second silicon substrate 12). The sensor S1also includes the pads 25 a, 30 a, 40 a provided on the periphery of thesensing portions 20, 31, 41 over the surface of the semiconductorsubstrate 10 (i.e., over the second silicon substrate 12).

The semiconductor acceleration sensor S1 also includes a plurality ofbonding wires 200, as illustrated in FIGS. 1 and 3. The bonding wires200 are in electrical communication with corresponding ones of the pads25 a, 30 a, 40 a for transmission of signals output by correspondingones of the sensing portions 20, 31, 41.

These bonding wires 200 can be formed of gold, aluminum, or the like.Also, the bonding wires 200 can be electrically bonding by a known wirebonding method, such as thermo-compression bonding, ultrasonic bonding(i.e., metal junction), or the like.

The pads 25 a, 30 a, and 40 a are electrically connected with a circuitchip, not shown, via these bonding wires 200. The circuit chip has adetector circuit (not shown) for processing the output signals from thesemiconductor acceleration sensor S1.

Furthermore, the sensor S1 includes a cover member 100. In oneembodiment, the cover member 100 is formed at least partially of resin,such as a resin film. The cover member 100 is provided over one surfaceof the semiconductor substrate 10. The cover member 100 includes acovering portion 103 and a coupling portion 101. The covering portion103 covers the sensing portions 20, 31, 41 such that the coveringportion 103 is disposed at a distance from the sensing portions 20, 31,41. The coupling portion 101 is coupled to the substrate 10 (i.e., overthe surface of the second silicon substrate 12 on the periphery of thesensing portions 20, 31, 41). The coupling portion 101 is also coupledto the pads 25 a, 30 a, 40 a. More specifically, the coupling portion101 of the cover member 100 is coupled to the semiconductor substrate 10at the surface of the second silicon substrate 12 at the rim of theopening 15. In this embodiment, the coupling portion 101 of the covermember 100 covers the pads 25 a, 30 a, 40 a.

As illustrated in FIG. 3, the bonding wires 200 are electricallyconnected to the pads 25 a, 30 a, 40 a even though the coupling portion101 of the cover member 100 is coupled to the pads 25 a, 30 a, 40 a.This electrical connection between one of the pads 25 a, 30 a, 40 a anda bonding wire 200 is indicated by reference numeral 110 in FIG. 3.Hereafter, it will be referred to as “pad-wire electrical connection110.”

More detailed description will be given to the construction of the covermember 100 and the pad-wire electrical connections 110 with reference toFIG. 4 as well. Although FIG. 4 is an enlarged view of the pad-wireelectrical connection 110 for the pad 25 a, it will be appreciated thatthe pad-wire electrical connection 110 could be the same for the otherpads 30 a, 40 a.

As illustrated in FIG. 4, the cover member 100 contains conductivemembers 102 at least at the portions of the cover member 100corresponding to the pads 25 a, 30 a, 40 a. That is, the cover member100 contains the conductive members 102 at portions where the pads 25 a,30 a, 40 a and the bonding wires 200 are to be electrically connectedwith each other. As will be explained in greater detail, the conductivemembers 102 establish electrical communication between the pads 25 a, 30a, 40 a and the corresponding bonding wires 200.

In the embodiment shown, the conductive members 102 are conductiveparticles. Thus, in the example illustrated in FIG. 4, a publicly knownanisotropic conductive film (ACF) is used as the material of the covermember 100. The cover member 100 is prepared by uniformly dispersing theconductive particles. More specifically, the conductive particles areformed of resin beads plated with gold or the like, and a material, suchas polyimide is used as a thermosetting adhesive. The thickness of thecover member 100 is, for example, approximately 50 μm, and the diameterof each conductive particle 102 is approximately 2 μm.

Such a cover member 100 can be easily formed by die forming or the like.The coupling portion 101 of the cover member 100 is coupled to the rimof the opening 15 by applying heat and pressure.

Furthermore, the covering portion 103 is dome shaped above the sensingportions 20, 31, 41, and the covering portion 103 protrudes away fromthe sensing portions 20, 31, 41 as shown in FIGS. 2 and 3. As shown, thedomed portion is substantially positioned over the opening 15. Theplanar shape of the domed portion 15 is rectangular and this shape issubstantially the same as the opening 15. Because the covering portion103 is dome shaped, space is created between the cover member 100 andthe sensing portions 20, 31, 41.

In one embodiment, the dome shape of the covering portion 103 is formedby press forming, in which the resin film is plastically deformed bywelding pressure. In another embodiment, the dome shape of the coveringportion 103 is formed by suction, in which the resin film is plasticallydeformed by suction force.

In one embodiment, the pad-wire electrical connections 110 are formed bycarrying out wire bonding on the pads 25 a, 30 a, 40 a over the covermember 100. More specifically, wire bonding is carried out on the pads25 a, 30 a, 40 a covered by the coupling portion 101 of the cover member100. Specifically, thermocompression bonding or ultrasonic bonding iscarried out to electrically connect the bonding wires 200 and thecorresponding pads 25 a, 30 a, 40 a. As such, the bonding wires 200 arepressed against the coupling portion 101 of the cover member 100, and asa result, the cover member 100 is deformed.

The deformed cover member 100 at the pad-wire electrical connections 110is illustrated in FIG. 4. As shown, the pressure from the bonding wire200 displaces the conductive particles 102 located at the pad-wireelectrical connection 110. Consequently, the bonding wires 200 and theconductive particles 102 are brought into contact with each other, andthe pads 25 a, 30 a, and 40 a and the conductive particles 102 arebrought into contact with each other. As a result, the bonding wires 200and the pads 25 a, 30 a, 40 a are electrically connected with each otherthrough the conductive particles 102 by metal junction or the like, andelectrical continuity is provided between them.

Description will be given to the detecting operation of thesemiconductor acceleration sensor S1 in this embodiment. This embodimentis so constructed that acceleration is detected based on change incapacitance at the sensing portions 20, 31, 41. That is, acceleration isdetected based on change in the capacitance between the movableelectrodes 24 and the fixed electrodes 31, 41 associated withapplication of acceleration.

In the semiconductor acceleration sensor S1, as mentioned above, theside faces (i.e. detector planes) of fixed electrodes 31, 41 areprovided opposite to the side faces (i.e. detector planes) of theindividual movable electrodes 24. A detection gap for detectingcapacitance is formed in each gap between the opposite side faces ofboth the electrodes.

First capacitance CS1 is detection capacitance between the left-sidefixed electrodes 31 and the movable electrodes 24. Second capacitanceCS2 is detection capacitance between the right-side fixed electrodes 41and the movable electrodes 24. When acceleration is applied to thesensor S1 in the X-direction, the movable portion 20 is integrallydisplaced in the direction of arrow X. As a result, the capacitance CS1and CS2 varies.

Therefore, acceleration in the direction of arrow X can be detectedbased on change in differential capacitance (CS1−CS2) produced due tothe change in the gaps between the left and right movable electrodes 24and the fixed electrodes 31, 41.

A signal based on this difference (CS1−CS2) in capacitance is outputtedas an output signal from the semiconductor acceleration sensor S1through the bonding wires 200. This signal is processed by theabove-mentioned circuit chip, from which the signal is finallyoutputted.

In order to manufacture the semiconductor acceleration sensor S1, aplurality of semiconductor substrates 10 are formed in a wafer. In otherwords, a semiconductor wafer is subjected to publicly knownsemiconductor processes. The wafer is then separated into chips toobtain the individual semiconductor substrates.

First, a mask with a shape corresponding to the above-mentioned beamstructures 20, 30, 40 is formed over the second silicon substrate 12 ofthe semiconductor substrate 10 in the form of wafer by photolithography.In other words, a mask is formed having openings corresponding to theabove-mentioned trenches 14.

Thereafter, trench etching is performed by dry etching or the like usingsuch gas as CF₄ or SF₆ to form the trenches 14 extended from the surfaceof the second silicon substrate 12 to the oxide film 13. Thus, a patternof the beam structures 20, 30, 40 is formed. Subsequently, the oxidefilm 13 is partly removed by sacrificial layer etching or the like usinghydrofluoric acid or the like to form the opening 15.

In addition, the pads 25 a, 30 a, 40 a are formed by photolithographyand sputtering film formation or the like. Thus, the movable portion 20is released, and the semiconductor acceleration sensor S1 is formed withrespect to each of multiple chips in the semiconductor wafer. In oneembodiment, neither the cover member 100 nor the bonding wires 200 havebeen affixed to the sensor S1.

Thus, at this point, the cover member 100 with respect to each of themultiple chips is prepared. The resin film of the cover member 100 isheated under pressure to a temperature close to the softeningtemperature of the film. Then, the cover member 100 for each chip iscoupled to the respective chip. In one embodiment, the coupling portion101 of the respective cover member 100 adheres to the substrate 10 dueto the stickiness of resin. More specifically, the coupling portion 101of the cover member 100 adheres to the area on the periphery of thesensing portions 20, 31, and 41, over the pads 25 a, 30 a, 40 a and overthe surface of the semiconductor substrate 10. Once the cover member 100is attached, the sensing portions 20, 31, 41 are covered by the coveringportion 103. That is, the cover member 100 is coupled to the rectangularframe-like peripheral portion around the opening 15 so that the pads 25a, 30 a, 40 a are covered, as illustrated in FIG. 1.

Subsequently, the semiconductor wafer with the attached cover members100 is cut into individual chips by dicing cut or the like. During thiscutting step, the sensing portions 20, 31, 41 are protected by the covermember 100.

Next, wire bonding is carried out for an individual chip between theportions of the cover member 100 positioned above the pads 25 a, 30 a,40 a and the circuit chip. The wire bonding is carried out so that theabove-mentioned deformation due to wire bonding occurs in the covermember 100.

More specifically, in this wire bonding step, the bonding wires 200 arepressed against the cover member 100 toward the pads 25 a, 30 a, 40 a.Thus, the cover member 100 is deformed so that the bonding wires 200 andconductive particles 102 are brought into contact with each other andthe pads 25 a, 30 a, 40 a and conductive particles 102 are brought intocontact with each other. As a result, electrical continuity between thepads 25 a, 30 a, 40 a and the bonding wires 200 is provided via theconductive particles 102.

Thus, the above-mentioned pad-wire electrical connections 110 areformed. As a result, the semiconductor acceleration sensor S1 in thisembodiment, illustrated in FIG. 1 to FIG. 4, is completed.

It will be appreciated that, in this embodiment of the semiconductoracceleration sensor S1, the cover member 100 covers the sensing portions20, 31, 41 and is also separated at a distance from the sensing portions20, 31, 41. Therefore, contact between the cover member 100 and thesensing portions 20, 31, 41 is unlikely, and displacement of the movableportion 20 due to application of acceleration is unlikely to behindered. Further, the cover member 100 protects the sensing portions20, 31, 41 from foreign matter. For this reason, the sensing portions20, 31, 41 are appropriately protected, and sensor characteristics canbe appropriately maintained.

In addition, as mentioned above, this cover member 100 can be easilyformed by die forming or the like, and the cover member 100 can becoupled to the semiconductor substrate 10 by applying pressure or thelike. Thus, the cover member 100 can be attached in a relatively simplemanner, especially as compared to cover members made of semiconductivematerial of the prior art.

The pads 25 a, 30 a, 40 a are provided under the coupling portion 101 ofthe cover member 100. Electrical continuity between the pads 25 a, 30 a,40 a and the bonding wires 200 is provided by forming theabove-mentioned pad-wire electrical connections 110. Therefore, signalscan be output from the sensing portions 20, 31, 41 via the bonding wires200.

Furthermore, because the pads 25 a, 30 a, 40 a are positioned under thecoupling portion 101 of the cover member 100, the size of thesemiconductor sensor S1 can be relatively small. This is because extraroom need not be provided for attachment of the cover member 100 betweenthe sensing portions 20, 31, 41 and the pads 25 a, 30 a, 40 a. Thus, thesemiconductor sensor S1 is more compact than those of the prior art.

Referring now to FIG. 5, another embodiment is shown. In thisembodiment, the conductive members 104 are metal plates disposed in thecover member 100. The metal plate 104 is formed of plate-like metal,such as copper, aluminum, iron, or the like. This embodiment of thecover member 100 can be manufactured by insert-molding the metal plates104 together with the resin of the cover member 100 or by a like method.

The pad-wire electrical connections 110 in this example are formed bycarrying out wire bonding on the pads 25 a, 30 a, 40 a, which arecovered with the coupling portion 101 of the cover member 100. Morespecifically, the coupling portion 101 of the cover member 100 isdeformed by pressing the bonding wires 200 against it, and the bondingwires 200 penetrate through the cover member 100 at those locations tocontact the corresponding metal plate 104. The metal plate 104 alsocontacts the corresponding pad 25 a, 30 a, 40 a. Thus, the bonding wires200 and the pads 25 a, 30 a, and 40 a are brought into electricalcommunication with each other via the metal plates 104.

Referring now to FIGS. 6 and 7, another embodiment is illustrated. Asshown, a metal foil 120 is included in the semiconductor sensor. In theembodiment shown, metal foil 120 is affixed to opposite surfaces of thecover member 100. The areas extended from the peripheral portions to theouter circumferential edges of the metal foil 120 are hatched for makingthe planar shape of the metal foil 120 clearly understandable.

This metal foil 120 can be formed of thin gold foil or the like. Also,in one embodiment, the cover member 100 with the metal foil 120 affixedthereto is formed by die forming. For example, melted resin 101containing conductive particles 102 is poured between sheets of metalfoil 120 to form the cover member 100. In the cover member 100 withmetal foil 120, the cover portion 103 is formed by subjecting the covermember 100 to press forming, suction forming, or the like as describedabove. Similar to the embodiment described above, the cover member 100of FIGS. 6 and 7 is coupled to the substrate 10 by applying heat andpressure. In this case, the metal foil 120 and the substrate 10 arebonded to each other by chemisorption or the like.

Also, the pad-wire electrical connections 110 are formed by wire bondingon the pads 25 a, 30 a, 40 a, which are covered with by the cover member100. More specifically, as shown in FIG. 6, the cover member 100 isdeformed and thinned over the pads 25 a, 30 a, 40 a by pressing thebonding wires 200 against the cover member 100. Pressing force from thebonding wire 200 brings the conductive particles 102 into contact witheach other as shown in FIG. 6, and as a result, the bonding wire 200 isin electrical communication with the corresponding pad 25 a, 30 a, 40 avia the conductive particles 102 and the metal foil 120.

In the embodiment shown in FIG. 7, the metal foil 120 is divided intothree regions on both sides of the cover member 100. It is separated incorrespondence with the individual sensing portions 20, 31, 41. That is,the metal foil is separated in correspondence with three members: themovable portion 20, the left-side fixed electrodes 31, and theright-side fixed electrodes 41. In other words, the metal foil 120 iselectrically separated in correspondence with the individual sensingportions 20, 31, 41. The metal foil 120 covers the individual sensingportions 20, 31, 41 together with the wiring portions and pads that areat the same potential as them, and the metal foil 120 electricallyshields them. Thus, in the embodiment shown in FIGS. 6 and 7, thesensing portions 20, 31, 41 are electrically shielded by the metal foil120.

More specifically, there is a possibility that the sensing portions 20,31, 41 could malfunction due to exogenous noise, such as electromagneticwaves. For instance, where the sensor S1 is used to detect accelerationof an automobile, exogenous noise may be caused by ignition noise andthe like. Change in the capacitance between the movable and fixedelectrodes generates a detection signal. Thus, there is a possibilitythat exogenous noise can have deleterious effect (i.e., the noise can besuperimposed on detection signals). However, the metal foil 120 affixedto the cover member 100 covers the sensing portions 20, 31, 41 toelectrically shield the sensing portions 20, 31, 41 against exogenousnoise. Thus, the sensor S1 can detect more accurately.

It will be appreciated that the conductive members 102, 104 provided inthe cover member 100 need not be included in the cover member 100 in theembodiment of FIGS. 6 and 7.

Referring now to FIGS. 8A and 8B, another embodiment is illustrated. Asshown, the cover member 100 includes a plurality of pores 101 a. In theembodiment of FIG. 8A, substantially the entire cover member 100includes the pores 101 a. In contrast, in the embodiment of FIG. 8B,pores 101 a are included locally above portions corresponding to thepads 25 a, 30 a, 40 a. The pores 101 a can be formed by forming thecover member 100 of resin foam or the like, forming the pores 101 a byetching or a needle-like jig, or another suitable method.

Furthermore, in the embodiment of FIGS. 8A and 8B, the pad-wireelectrical connections 110 are formed by wire bonding on the regionsover the pads 25 a, 30 a, 40 a. For example, the end portions of thebonding wires 200 can be partly melted by energy to flow into the pores101 a to contact the corresponding pad 25 a, 30 a, 40 a. In FIGS. 8A and8B, the so-called “flow portion” (i.e., the melted portion) is labeledwith the reference numeral 105. The flow portions 105 are made of aconductive material to thereby bring the bonding wires 200 intoelectrical communication with the corresponding pad 25 a, 30 a, 40 a.

As illustrated in FIGS. 8A and 8B, the cover member 100 is also deformed(i.e., thinned) by pressing the bonding wires 200 against them. Inaddition, electrical continuity is provided between the bonding wires200 and the corresponding pads 25 a, 30 a, 40 a via the flow members 105within the fine pores 101 a.

In the above-mentioned embodiments, conductive members 102, 104 arecontained in the cover member 100. Then, anisotropic conductiveconnection is implemented by pressing the bonding wires 200 into thecover member 100. However, the pad-wire electrical connections 110 arenot limited to this construction.

For example, pad-wire electrical connections 110 may be formed asillustrated in FIG. 9A. That is, the pad-wire electrical connections 110may be formed by pressing the bonding wires 200 into the cover memberuntil the bonding wires 200 penetrate through the cover member 100 andcontact the corresponding pads 25 a, 30 a, 40 a.

In another embodiment, the cover member 100 includes a plurality ofopenings 106 in an area above the pads 25 a, 30 a, 40 a. The openings106 expose a portion of a corresponding pad 25 a, 30 a, 40 a andprovides access to the corresponding pad 25 a, 30 a, 40 a. The openings106 can be formed by press work, die forming, or the like.

Thus, in this embodiment, the pad-wire electrical connections 110 havesuch openings 106. Continuity between pads and bonding wires can beprovided through the openings 106 by carrying out wire bonding on theportions of the pads 25 a, 30 a, 40 a exposed in the openings 106.

Furthermore, in the embodiments described above with conductiveparticles 102, the conductive particles 102 are dispersed throughout thecover member 100. However, the conductive particles 102 can also belocally included in portions of the cover member 100 corresponding tothe pads 25 a, 30 a, 40 a without departing from the scope of thepresent disclosure.

In addition, in the embodiment of the cover member 100 with the metalfoil 120, the metal foil 120 can be included on only one surface of thecover member 100 without departing from the scope of the presentdisclosure. Furthermore, in the cover member 100 illustrated in FIG. 6,metal plates 104 (FIG. 5) may be used in place of the conductiveparticles 102 without departing from the scope of the presentdisclosure.

Additionally, in the manufacturing method for the sensor S1, multipleattached cover members 100 are coupled to the semiconductor substrates10 in the form of wafer (i.e., a semiconductor wafer), and then theindividual chips are separated. In another embodiment, individual covermembers 100 are formed, and the cover member 100 are coupled toindividual chips.

Moreover, any other material than polyimide can be used for the covermember 100.

Still further, the sensor S1 may be of any suitable type, such as anacceleration sensor, an angular speed sensor, or any other semiconductormechanical quantity sensor, etc. These semiconductor mechanical quantitysensors include, over one surface of a semiconductor substrate 10,movable electrodes 24 that can be displaced by application of amechanical quantity and fixed electrodes 31, 41 placed opposite to themovable electrodes 24. The sensors also include pads 25 a, 30 a, 40 a onthe periphery of both the electrodes 24, 31, 42 over the one surface ofthe semiconductor substrate 10, and bonding wires 200 are electricallyconnected to the pads 25 a, 30 a, 40 a for transmitting signals outputby the pads 25 a, 30 a, 40 a. The sensor S1 may also be an SAE filterelement used in cellular phones and the like and detect a predeterminedfrequency of radio waves.

Thus, while only the selected embodiments have been chosen to illustratethe present invention, it will be apparent to those skilled in the artthat various changes and modifications can be made therein withoutdeparting from the scope of the invention as defined in the appendedclaims. Furthermore, the foregoing description of the embodimentsaccording to the present invention is provided for illustration only,and not for the purpose of limiting the invention as defined by theappended claims and their equivalents.

1-20. (canceled)
 21. A semiconductor sensor comprising: a semiconductorsubstrate; a sensing portion provided on the semiconductor substrate; apad in electrical communication with the sensing portion and provided onthe semiconductor substrate; a bonding wire in electrical communicationwith the pad; and a cover member comprising a covering portion disposedover the semiconductor substrate for covering the sensing portion suchthat the covering portion is separated at a distance from the sensingportion, wherein the cover member further comprises a coupling portionprovided on the semiconductor substrate at an area including the pad andfor enabling electrical connection of the pad with the bonding wiretherethrough, wherein the bonding wire penetrates through the covermember so as to contact the pad.
 22. The semiconductor sensor accordingto claim 21, wherein the covering portion is dome shaped and protrudesaway from the sensing portion.
 23. The semiconductor sensor according toclaim 21, wherein the cover member is made of resin.
 24. A method ofmanufacturing a semiconductor sensor comprising: providing a sensingportion on a semiconductor substrate; providing a pad in electricalcommunication with the sensing portion on the semiconductor substrate;providing a cover member comprising a covering portion and a couplingportion; providing the coupling portion of the cover member on thesemiconductor substrate on an area including the pads such that thecovering portion covers the sensing portion and such that the coveringportion is separated at a distance from the sensing portion; andelectrically coupling a bonding wire to the pad through the couplingportion for transmission of signals output by the sensing portion,wherein electrically coupling the bonding wire comprises penetratingthrough the cover member such that the bonding wire contacts the pad.25. The method according to claim 24, wherein the covering portion isdome shaped and protrudes away from the sensing portion.